circulated in Brick Trouglis. 



267 



eight feet wide ; it was originally used for propagation, but without the means 



of that useful stimulant for cuttings, &c., bottom heat, instead of which it had 



a platform of tiles three feet six inches in width, raised 



on brick arches, and running the whole length of the 



house, being of a sufficient height to make it convenient 



for placing pots of cuttings, &c., upon. The means of 



heating used was a common smoke flue, also raised on 



brick arches, and occupying two feet in width ; the 



remaining space was taken up by the path. 



All that was found necessary to do in altering it to 

 its present state, after procuring a boiler, was to pull 

 down the smoke flue, which was next the front wall, 

 and make the bench on which it stood on the same 

 level with the platform on the other or back side of 

 the path ; this done, two troughs were erected upon 

 it for heating the atmosphere of the house, as repre- 

 sented in Jig. 67. at h b. These troughs are formed 

 by partitions two bricks on edge deep, set in cement, 

 the bottom and inner sides of the lower bricks only 

 being plastered with the same material. A covering 

 is formed of common tiles, which were in use for co- 

 vering the smoke flue. On the three feet six inches 

 platform are also erected two troughs {d d), as a me- 

 dium for bottom heat. They occupy its full width, but 

 are only formed one brick on edge deep (d d), also 

 set in cement, and plastered with the same inside. 

 Common plain tiles (as they are termed) are used for 

 a covering for these troughs ; but, as they are only 

 nine inches in length, it was found necessary to support 

 the end of each in the middle of each trough by means 

 of a row of brick on edge laid in without cement, so 

 as not to raise them above the level of the side bricks, 

 and left pigeon-holed. The tiles were then bedded on 

 in cement, all the joints being afterwards carefully 

 pointed. This forms another platform, which is co- 

 vered by about six inches of old tan for receiving pots 

 of cuttings, &c., which tan is kept compactly together 

 by a brick on edge, also set in cement along each side, 

 as shown in the section. 



The boiler is placed at the extreme end of the house 

 at e, inside, being supplied with fuel from the out- 

 side ; it has a short piece of four-inch iron pipe to 

 supply the two flow troughs, as represented by the 

 dotted lines at e, and two return pipes which enter it 

 at opposite sides. This boiler is of novel construction, 

 the invention of Mr. Thomson, late gardener at Syon 

 House, and is well calculated for economy, both in 

 fuel and labour; having a much greater surface ex- 

 posed to the action of the fire than any boiler I have 

 ever seen of the same size. 



The water in the troughs rarely exceeds an inch in depth, with which 

 quantity we can keep, with the greatest nicety, both the temperature of the 

 house and the bottom heat to any required degree. I must not omit to men- 

 tion, that in each flow trough is placed a sluice, formed by a piece of slate 

 pushed down in two grooves in the cement, so that the water may be stopped 

 from circulating in either at pleasure. 



So satisfactory has the system proved here, and so very moderate in expense, 

 a bricklayer and his labourer having completed the whole in a few days with 

 two and a half tubs of cement, the old materials which formed the smoke 



Wl 



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•1^/2- o 7 Si' 



Ijij ! — ! ! — 1 ! — ! — 1 



Fig. 67. Plan and Section 

 of a Propagaling-House 

 in the Hatnmersmith 

 Nitrserj/, heated hy hot 

 Water circulating in 

 Bride Troughs lined 

 with Cement. 



